In U.S. Pat. Nos. 4,094,696, 4,073,659, 4,193,815, 4,282,037, 4,621,108 and 4,722,953 there are disclosed gilsonite, asphalt and various other bituminous polymer emulsion compositions. A number of the compositions are effective for paving surfaces, and others for producing coatings, insulation board materials, etc. As useful as these materials are, the instability of the emulsions frequently make such products difficult to use after a period of storage. Shelf life of the prepared emulsions and the ability of the composition to resist deterioration over long periods of use after being applied to a surface and especially when exposed to alternating periods of extreme weather conditions, leave something to be desired. These prior art compositions are formed at elevated temperatures and generally must be applied or used at elevated temperatures. It is to still further improved gilsonite emulsion compositions having superior characteristics as well as a number of other uses that the compositions of the present invention are directed. Heretofore, the gilsonite mixtures have used heat to soften the gilsonite and aromatic and aliphatic organic solvents to solubilize the gilsonite. These solvents are now limited in usage by legislation such as the Clean Air Act. Water base coatings and other products are needed to replace those products which have volatile organic compounds as the solvent or vehicle. It has also been found that the prior art bituminous water emulsions lack the ability to prepare suitable wood stains and printing inks when reduced substantially by addition of water. The unique properties of gilsonite, contrasted with bitumens in general present unique problems in the formation of stable aqueous emulsions. When thinned with water, the prior art emulsion compositions tend to break and separate, rendering them of little value for use as wood stains and printing inks. Prior art emulsions have been formed at elevated temperatures. There is a need to provide a stable and secure emulsification system and method for gilsonite, in part due to the unique properties of this specific category of bitumen.
It has been found that a prior art emulsification system using waste sulfite liquor as the emulsification agent for heat polymerized synthetic bitumen cannot effectively emulsify gilsonite at non-elevated temperatures, and the mixture attempted according to the teachings of the patent disclosing this prior art (U.S. Pat. No. 2,789,097 issued to Mr. Rappleyea) was not able to provide a stable gilsonite-water emulsion when formed and processed at room temperature. Other unmodified asphaltic mixtures using other prior art emulsification and surfactant agents frequently exhibit brittleness. Since there is a need for a relatively high degree of flexibility particularly when the emulsion is applied to printing ink, such compositions cannot be effectively applied to use as printing ink. Chemicals heretofore added to the asphaltic emulsions, include various emulsifiers and dispersants, such as polymers to improve flexibility, extensibility and toughness, emulsifiers to help maintain a more nearly stable emulsion, dispersants, clays, fillers, pigments and other materials added for special purposes. Traditional mixing or blending procedures are used to incorporate the mentioned chemicals into the asphaltic emulsions. The asphalt emulsion known to the prior art find use as road slurry sealers but cannot be used in wood stains and printers ink due to incompatibility with ingredients needed to manufacture such products. Heretofore none of the prior art emulsions have been found effective to provide a refined and stable emulsion of gilsonite for use as wood stains, printing ink, automotive undercoating emulsions and similar applications.
Aqueous bituminous emulsions heretofore known normally consist of emulsifiers such as clays, or combinations of cationic, nonionic or anionic emulsifying agents combined with the bitumen at an elevated temperature. The surface active agents are necessary to provide emulsion stability. After the emulsion particles coalesce, the presence of the surface active agents detracts from water resistant properties. The addition of a polymer emulsion to the asphaltic emulsion enhances the properties of the resulting coating material. However, the resulting film may have some degree of water solubility so that the water resistance of the cured material is adversely affected. There is a need in the industry for a simple emulsification process and composition which results in a highly stable emulsion for storage purposes yet provides advantageous properties for use of the resulting material in applications such as wood stains, water based printing inks and other similar applications. There is also a need in the industry for adhesive emulsions and adhesives made with water reducible resins including gilsonite which have enhanced shear and peel strength. Other well known uses of gilsonite, including asphalt modification, oil drilling cement slurries, paints and the like can benefit from improved emulsion characteristics.